This is a General Clinical Research Center with 8 beds for both adults and children. Studies either planned or in progress include the description of new genetic syndromes and studies of twins: studies of the regulation of secretion of vasopressin and parathyroid hormone in normal and abnormal diseased states; studies of the mechanism and treatment of the abnormal calcium and phosphorus metabolism in Paget's disease, pseudohypoparathyroidism and sarcoidosis; and studies of the pathogenesis and management of patients with hypertension.